The writing was on the wall, and now the VW diesel-emissions cheating scandal has claimed another victim: Audi research and development chief Ulrich Hackenberg is officially out. He had been on leave since the early stages of the VW Group’s still unfolding situation. Hackenberg will be succeeded by Stefan Knirsch [pictured above with the author], an engineer with vast experience both within Audi and at other companies.

Hackenberg’s departure underscores the gravity of the diesel scandal; it is not clear whether he knew about the manipulations, but he was in charge of Volkswagen R&D between 2007 and 2013, and apparently took full responsibility now, although Audi and VW are abstaining from any official finger-pointing at this point. After his tenure at VW, Hackenberg moved to head Audi R&D after the sudden ousting of Wolfgang Dürheimer, who has since resurfaced as CEO of Bentley and Bugatti.

Hackenberg’s contribution to the VW Group’s current portfolio is invaluable; he spearheaded Audi and VW’s MLB and MQB modular architectures, and he has overseen the application of advanced technologies to many VW Group models. A true car enthusiast and approachable to his engineering and design staff, he was a popular figure in the company and among his staff.

Stefan Knirsch could be the right man to fill his shoes. The engineer started his career at Audi in 1990 before moving to Porsche in 1996, where he became head of engine development in 2001. In 2007, Knirsch moved to lead Porsche’s aftersales activities; three years later, he became head of supplier Pierburg before returning to Audi in 2013. In June 2015, he left Audi when, according to the rumor mill, he was on track for a top executive position at Daimler. Now Audi has pulled him back into its fold.

Knirsch will slide into his new position on January 1, 2016. The move was announced by Matthias Müller, who is not just CEO of the Volkswagen Group, but also head of Audi’s supervisory board—a position he assumed today. That Audi job is traditionally held by the CEO of VW, as the automotive juggernaut holds more than 99 percent of Audi’s shares. Despite stepping down as VW Group CEO in September, Martin Winterkorn hung on to his leadership of the Audi supervisory board until mid-November.